Question

When a neutral or alkaline solution of thiosulphate is treated with the $[Ni{{(en)}_{3}}{{(N{{O}_{3}})}_{2}}]$ complex then,
A. Green precipitate is obtained
B. Brown precipitate is obtained
C. Violet precipitate is obtained
D. Yellow precipitate is obtained

Answer 1

Acids are generally those substances which are capable of donating a proton i.e. hydrogen atom to another substance while bases are those substances which are able to accept a hydrogen ion from an acid. Alkaline solutions are generally known as basic solutions.

Complete answer:
Aqueous solutions are also considered as those solutions who have pH value less than 7 whereas for neutral solution the pH value remains fixed i.e. 7. Thiosulphate is generally known as the oxyanion of sulphur atom here the prefix thio indicates the presence of sulphur group. Thiosulphate is represented by the chemical formula ${{S}_{2}}{{O}_{3}}^{2-}$. The shape of thiosulphate is tetrahedral in nature. It occurs naturally and can also be produced by certain biochemical processes.
When a neutral or alkaline solution of thiosulphate is treated with the $[Ni{{(en)}_{3}}{{(N{{O}_{3}})}_{2}}]$ complex then green precipitate is observed reaction can be shown as follows:
$[Ni{{(en)}_{3}}{{(N{{O}_{3}})}_{2}}]+{{S}_{2}}{{O}_{3}}^{^{2-}}\to [Ni{{(en)}_{3}}]{{S}_{2}}{{O}_{3}}\ Green\ \text{ppt}$

Hence from the above reaction we can consider that option A is the correct answer.

Note:
If we mix equal amounts of an acid and a base then two chemicals essentially cancel out each other and produce salt and water. Mixing equal amounts of a strong acid with a strong base results in a neutral solution whose pH value remains 7 and this type of reaction is known as neutralization reaction.